Abstract

Urbanisation is the result of the increasing density of human population and the movement of populations to urban centres. It isolates populations of wetland species by removing and fragmenting habitat. Isolation can be damaging to wetland species such as frogs and turtles that rely on terrestrial vegetation for habitat and to assist in their movements between wetlands. This fragmentation may also be damaging to meta-population networks that existed within the natural environment. It is suspected that the residential gardens that have replaced native areas may be able to provide an alternative habitat source for these wetlands species.

The study site contained 236 residences within the City of Melville. Gardens in this area were assessed for the habitat they provided for local wetland species. To supplement this, residents completed a survey (45% response rate) with questions regarding gardening choices and attitudes and wetland species that they had seen in their gardens.

Turtles were found to be moving through one main section of the urban environment, which was the shortest and most accessible route between the wetlands. No relationship between any type of garden habitat and turtle presence was identified.

Frogs exhibited an inverse distance relationship with wetlands. This is contrary to findings in native areas, possibly due to impediments to movement present in the residential area. The probability of frog presence increased with the percentage cover of shrubs below 0.5m. It is highly likely that other ground cover types influence the presence of frogs, as many species of frogs utilise terrestrial habitat during the non-breeding season, but due to low occurrence of some types of ground cover these were not found to be significantly related to frog presence. Subdivision may be leading to an increase in paving and decrease of garden size. This will result in the loss of potential habitat for wetland species in the area.

Participants in the survey generally had a positive attitude towards the environment. This could be used to encourage and offer incentives for residents to increase the vegetated land cover within their gardens. The findings of this study can be used to inform residents and the local councils how their choices can impact on connectivity in the urban environment.